National Natural Science Foundation of China (No. 41476170) and Chinese Polar Environment Comprehensive Investigation and Assessment Programs (Nos. CHINARE2015-03-01/04-03/04-04). JW was supported by the NOAA CPO Office of Arctic Research through RUSALCA project, which was GLERL Contribution (No. 1837). PH was supported by the Antarctic Climate and Ecosystems CRC program. This work contributes to Australian Antarctic Science project (No. 4301).

摘要

In summer 2014, sea ice morphological characteristics were investigated in the 135°-175°W sector of the Arctic Ocean using in situ, shipborne, and remote sensing measurements. Sea ice in this sector was deformed and compact compared to previous observations. The average ice area in the region (70°-82.5°N, 135°-175°W) was 7.6 × 105km2for 29 July through 6 September 2014, the fourth largest record between 2003 and 2014. This can be attributed to the enhanced multiyear sea ice inflow from north of the Canadian Arctic Archipelago from September 2013 to August 2014. Multiyear ice coverage in the study region on 30 April 2014 was 55%, which was larger than the values in 2005-2013. During the melt season of 2014, the Arctic Dipole had a positive anomaly, associated with enhanced southerly wind. In summer 2014 the marginal ice zone exhibited a distinct ice retreat, whereas the pack ice zone (PIZ) showed strong persistence due to the large coverage of multiyear ice. The northward retreat of the PIZ boundary was < 100 km from late July through early September 2014. In the PIZ of 76-80.5°N, average ice thickness weighted by ice concentration, obtained by shipborne measurements in August 2014 was 0.54 m thicker than that obtained in August 2010 due to enhanced ice deformation and less open waters in 2014. At 81°N, sea ice with modal thickness of 1.48 m reached thermodynamic balance by late August 2014, which was much earlier than that in 2010.